Summarize this article in one sentence.
If you are coming from another country, then you will need to fly into an international airport. Traveling to Toronto Pearson International Airport (YYZ) will also save you the trouble of going through a second border if you plan to visit the Canadian falls.  Toronto Pearson International Airport is also a good option if you are traveling from the US or Canada because this airport will have lots of flights to choose from. This airport is a 1.5 hour drive from Niagara Falls. You might be able to find a good deal at a smaller airport. However, keep in mind that Billy Bishop Toronto City Airport (YTZ) does not have international flights other than between the US and Canada, so it will not be a good choice if you are coming from another country. This airport is a 1.5 hour drive from Niagara Falls. This is a smaller airport, but it offers lots of flights within North America. Check to see if you can get a good deal on a flight into John C Munro Hamilton International Airport (YMC). This airport is about 1 hour away from Niagara Falls. This is a great option if you are flying from within the United States, or if you only want to visit the US side of Niagara Falls. Keep in mind that you will need to have a passport to cross the border and visit the Canadian side of Niagara Falls. This airport is 45 minutes away from Niagara Falls.

Summary:
Fly to Toronto Pearson International Airport outside the US or Canada. Select Billy Bishop Toronto City Airport from the US or Canada. Fly John C Munro Hamilton International Airport from North America. Opt for Buffalo Niagara International Airport (BUF) to see the US falls.